Tools for Predicting Optical Damage on Inertial Confinement Fusion-Class Laser Systems (open access)

Tools for Predicting Optical Damage on Inertial Confinement Fusion-Class Laser Systems

Operating a fusion-class laser to its full potential requires a balance of operating constraints. On the one hand, the total laser energy delivered must be high enough to give an acceptable probability for ignition success. On the other hand, the laser-induced optical damage levels must be low enough to be acceptably handled with the available infrastructure and budget for optics recycle. Our research goal was to develop the models, database structures, and algorithmic tools (which we collectively refer to as ''Loop Tools'') needed to successfully maintain this balance. Predictive models are needed to plan for and manage the impact of shot campaigns from proposal, to shot, and beyond, covering a time span of years. The cost of a proposed shot campaign must be determined from these models, and governance boards must decide, based on predictions, whether to incorporate a given campaign into the facility shot plan based upon available resources. Predictive models are often built on damage ''rules'' derived from small beam damage tests on small optics. These off-line studies vary the energy, pulse-shape and wavelength in order to understand how these variables influence the initiation of damage sites and how initiated damage sites can grow upon further exposure to …
Date: December 20, 2010
Creator: Nostrand, M. C.; Carr, C. W.; Liao, Z. M.; Honig, J.; Spaeth, M. L.; Manes, K. R. et al.
Object Type: Report
System: The UNT Digital Library
Comment on "Wall Forces Produced During ITER Disruptions" by H. R. Strauss, R. Paccagnella, and J. Breslau (PHYSICS OF PLASMAS 17, 082505 (2010) (open access)

Comment on "Wall Forces Produced During ITER Disruptions" by H. R. Strauss, R. Paccagnella, and J. Breslau (PHYSICS OF PLASMAS 17, 082505 (2010)

The paper by H.R. Strauss presents numerical simulations, which pretend to describe the disruption instability in ITER device. The simulations were performed with numerical code M3D, described in Ref.[7] of the paper.
Date: October 20, 2010
Creator: Zakharov, Leonid E.
Object Type: Report
System: The UNT Digital Library
ARM CLASIC ER2 CRS/EDOP (open access)

ARM CLASIC ER2 CRS/EDOP

Data was taken with the NASA ER-2 aircraft with the Cloud Radar System and other instruments in conjunction with the DOE ARM CLASIC field campaign. The flights were near the SGP site in north Central Oklahoma and targeted small developing convection. The CRS is a 94 GHz nadir pointing Doppler radar. Also on board the ER-2 was the Cloud Physics Lidar (CPL). Seven science flights were conducted but the weather conditions did not cooperate in that there was neither developing convection, or there was heavy rain.
Date: December 20, 2010
Creator: Heymsfield, Gerald
Object Type: Text
System: The UNT Digital Library
Review of the Recent Frequency Performance of the Eastern, Western and ERCOT Interconnections (open access)

Review of the Recent Frequency Performance of the Eastern, Western and ERCOT Interconnections

The reliable operation of an electric power system depends on careful management of the balance between generation and load to ensure that system frequency is maintained within narrow bounds around a scheduled value. Yet, maintaining frequency at the scheduled value is challenging because the load served is continuously changing, and occasionally, events such as the sudden loss of a large generation plant or large amount of load, cause frequency to deviate abruptly. This report reviews the recent history of frequency performance for all three U.S. interconnections: Eastern, Western, and the Electric Reliability Council of Texas (ERCOT). The review is based on data collected by the North American Electric Reliability Corporation (NERC). The review focuses on frequency response, which measures the performance of the interconnections immediately following sudden, large imbalances between load and generation. Trends in frequency response are presented and preliminary efforts are made to relate frequency response to other aspects of frequency performance and to examine aspects of the methods used to calculate frequency response.
Date: December 20, 2010
Creator: Lacommare, Kristina S H
Object Type: Report
System: The UNT Digital Library
Use of Frequency Response Metrics to Assess the Planning and Operating Requirements for Reliable Integration of Variable Renewable Generation (open access)

Use of Frequency Response Metrics to Assess the Planning and Operating Requirements for Reliable Integration of Variable Renewable Generation

An interconnected electric power system is a complex system that must be operated within a safe frequency range in order to reliably maintain the instantaneous balance between generation and load. This is accomplished by ensuring that adequate resources are available to respond to expected and unexpected imbalances and restoring frequency to its scheduled value in order to ensure uninterrupted electric service to customers. Electrical systems must be flexible enough to reliably operate under a variety of"change" scenarios. System planners and operators must understand how other parts of the system change in response to the initial change, and need tools to manage such changes to ensure reliable operation within the scheduled frequency range. This report presents a systematic approach to identifying metrics that are useful for operating and planning a reliable system with increased amounts of variable renewable generation which builds on existing industry practices for frequency control after unexpected loss of a large amount of generation. The report introduces a set of metrics or tools for measuring the adequacy of frequency response within an interconnection. Based on the concept of the frequency nadir, these metrics take advantage of new information gathering and processing capabilities that system operators are developing for …
Date: December 20, 2010
Creator: Eto, Joseph H.; Undrill, John; Mackin, Peter; Daschmans, Ron; Williams, Ben; Haney, Brian et al.
Object Type: Report
System: The UNT Digital Library
Advanced Combustion Diagnostics and Control for Furnaces, Fired Heaters and Boilers (open access)

Advanced Combustion Diagnostics and Control for Furnaces, Fired Heaters and Boilers

The objective of this project was to develop and apply enabling tools and methods towards advanced combustion diagnostics and control of fired-equipment in large-scale petrochemical manufacturing. There are a number of technology gaps and opportunities for combustion optimization, including technologies involving advanced in-situ measurements, modeling, and thermal imaging. These technologies intersect most of manufacturing and energy systems within the chemical industry. This project leveraged the success of a previous DOE funded project led by Dow, where we co-developed an in-situ tunable diode laser (TDL) analyzer platform (with Analytical Specialties Inc, now owned by Yokogawa Electric Corp.). The TDL platform has been tested and proven in a number of combustion processes within Dow and outside of Dow. The primary focus of this project was on combustion diagnostics and control applied towards furnaces, fired heaters and boilers. Special emphasis was placed on the development and application of in-situ measurements for O2, CO and methane since these combustion gases are key variables in optimizing and controlling combustion processes safely. Current best practice in the industry relies on measurements that suffer from serious performance gaps such as limited sampling volume (point measurements), poor precision and accuracy, and poor reliability. Phase I of the project …
Date: March 20, 2010
Creator: Tate, J. D.; Le, Linh D.; Knittel,Trevor & Cowie, Alan
Object Type: Report
System: The UNT Digital Library
Office of the Chief Financial Officer Annual Report 2010 (open access)

Office of the Chief Financial Officer Annual Report 2010

In March, a review team consisting of CFOs from other national laboratories, industry, and members of the University of California Office of the President (UCOP) convened for three days to conduct a comprehensive peer review of the OCFO. This was the first time in almost a decade that the financial operations of the Laboratory had been reviewed. The Committee relayed their observations on our strengths, and their very thoughtful recommendations for improvement, which we are actively pursuing. These improvements, when implemented, will benefit the entire Laboratory for many years to come. The complete report is available on the OCFO website (www.lbl.gov/Workplace/CFO). In August, the senior management team of the OCFO participated in a strategic planning retreat. The purpose of the two and a half day exercise was, of course, to update our strategic plan, but instead of spending days developing a written document, we enlisted the expertise of a seasoned journalist who also happens to be a very talented graphic artist. He listened carefully to our ideas and committed them to a visual roadmap. All members of the OCFO, Business Managers, and the Laboratory Leadership Team reviewed this draft roadmap. By having a completely visual strategic plan that is posted …
Date: December 20, 2010
Creator: Fernandez, Jeffrey
Object Type: Report
System: The UNT Digital Library
National Transport Code Collaboration (NTCC) PTRANSP, Final Report to the US Department of Energy for the Period August 1, 2007 Through July 31, 2010 (open access)

National Transport Code Collaboration (NTCC) PTRANSP, Final Report to the US Department of Energy for the Period August 1, 2007 Through July 31, 2010

This report describes the work done under U.S. Department of Energy grant number DE-FG02-07ER54935 for the period ending July 31, 2010. The goal of this project was to provide predictive transport analysis to the PTRANSP code. Our contribution to this effort consisted of three parts: (a) a predictive solver suitable for use with highly non-linear transport models and installation of the turbulent confinement models GLF23 and TGLF, (b) an interface of this solver with the PTRANSP code, and (c) initial development of an EPED1 edge pedestal model interface with PTRANSP. PTRANSP has been installed locally on this cluster by importing a complete PTRANSP build environment that always contains the proper version of the libraries and other object files that PTRANSP requires. The GCNMP package and its interface code have been added to the SVN repository at PPPL.
Date: August 20, 2010
Creator: Lao, Lang L.; St John, Holger; Staebler, Gary M. & Snyder, Phil B.
Object Type: Report
System: The UNT Digital Library
TOXNET and Beyond: Using the National Library of Medicine's Environmental Health and Toxicology Portal (open access)

TOXNET and Beyond: Using the National Library of Medicine's Environmental Health and Toxicology Portal

The National Library of Medicine's Environmental Health and Toxicology Portal provides access to numerous databases that can help you explore environmental chemicals and risks. TOXNET and Beyond: Using NLM's Environmental Health and Toxicology Portal conveys the fundamentals of searching the NLM's TOXNET system of databases in chemistry, toxicology, environmental health, and related fields. In addition to TOXNET, the course will highlight various resources available through the Environmental Health and Toxicology Portal.
Date: October 20, 2010
Creator: Templin-Branner, W.
Object Type: Book
System: The UNT Digital Library
Hydrodynamic Modeling Analysis of Union Slough Restoration Project in Snohomish River, Washington (open access)

Hydrodynamic Modeling Analysis of Union Slough Restoration Project in Snohomish River, Washington

A modeling study was conducted to evaluate additional project design scenarios at the Union Slough restoration/mitigation site during low tide and to provide recommendations for finish-grade elevations to achieve desired drainage. This was accomplished using the Snohomish River hydrodynamic model developed previously by PNNL.
Date: December 20, 2010
Creator: Yang, Zhaoqing & Wang, Taiping
Object Type: Report
System: The UNT Digital Library
Analysis of Wind Power and Load Data at Multiple Time Scales (open access)

Analysis of Wind Power and Load Data at Multiple Time Scales

In this study we develop and apply new methods of data analysis for high resolution wind power and system load time series, to improve our understanding of how to characterize highly variable wind power output and the correlations between wind power and load. These methods are applied to wind and load data from the ERCOT region, and wind power output from the PJM and NYISO areas. We use a wavelet transform to apply mathematically well-defined operations of smoothing and differencing to the time series data. This approach produces a set of time series of the changes in wind power and load (or ?deltas?), over a range of times scales from a few seconds to approximately one hour. A number of statistical measures of these time series are calculated. We present sample distributions, and devise a method for fitting the empirical distribution shape in the tails. We also evaluate the degree of serial correlation, and linear correlation between wind and load. Our examination of the data shows clearly that the deltas do not follow a Gaussian shape; the distribution is exponential near the center and appears to follow a power law for larger fluctuations. Gaussian distributions are frequently used in modeling …
Date: December 20, 2010
Creator: Coughlin, Katie & Eto, J.H.
Object Type: Report
System: The UNT Digital Library
Preface to International Workshop on X-ray Mirror Design, Fabrication, and Metrology (open access)

Preface to International Workshop on X-ray Mirror Design, Fabrication, and Metrology

The International Workshop on X-Ray Mirror Design, Fabrication, and Metrology (IWXM), Osaka, Japan, was held as a satellite meeting of the Conference on Synchrotron Radiation Instrumentation (SRI) 2009, Melbourne, Australia, in October, 2009. The workshop was organized by a collaboration of scientists from a number of leading synchrotron institutions and universities around the World, such as Osaka University, SPring-8, KEK (Japan), ALS, APS and NSLS (USA), ELETTRA (Italy), ESRF, Synchrotron SOLEIL (France), BESSY (Germany), Diamond (UK), SSRF (China), NSRRC (Taiwan) and PAL (Korea). The workshop followed a series of parallel workshops focused on metrology (1st, 2nd and 3rd International Workshop on Metrology for X-ray and Neutron Optics) and on active X-ray optics (1st and 2nd X-ray and XUV Active Optics Workshop, ACTOP06 and ACTOP08) and included the 3rd workshop on X-ray and EUV active optics (ACTOP09). The workshop brought together more than 100 participants: manufacturers, optical and mechanical engineers, designers, and users of X-ray optics; allowing for free exchange of ideas, highlighting of existing problems and challenges, and searching for ways to improve existing instrumentation for sub-microradian and sub-nanometer accuracy. A visit to the Osaka University mirror fabrication laboratory, SPring-8, and the X-ray free electron laser (XFEL) facility was included …
Date: April 20, 2010
Creator: Yamauchi, Kazuto; Yashchuk, Valeriy V. & Cocco, Daniele
Object Type: Article
System: The UNT Digital Library
Comment on "Wall Forces Produced During ITER Disruptions" by H. R. Strauss, R. Paccagnella, and J. Breslau (PHYSICS OF PLASMAS 17, 082505 (2010) (open access)

Comment on "Wall Forces Produced During ITER Disruptions" by H. R. Strauss, R. Paccagnella, and J. Breslau (PHYSICS OF PLASMAS 17, 082505 (2010)

The paper by H.R. Strauss presents numerical simulations, which pretend to describe the disruption instability in ITER device. The simulations were performed with numerical code M3D, described in Ref.[7] of the paper.
Date: October 20, 2010
Creator: Zakharov, Leonid E.
Object Type: Report
System: The UNT Digital Library
The Northwest Geysers EGS Demonstration Project Phase 1: Pre-stimulation coupled geomechanical modeling to guide stimulation and monitoring plans (open access)

The Northwest Geysers EGS Demonstration Project Phase 1: Pre-stimulation coupled geomechanical modeling to guide stimulation and monitoring plans

This paper presents activities and results associated with Phase 1 (pre-stimulation phase) of an Enhanced Geothermal System (EGS) demonstration project at the northwest part of The Geysers geothermal field, California. The paper presents development of a 3-D geological model, coupled thermal-hydraulic-mechanical (THM) modeling of proposed stimulation injection as well as current plans for stimulation and monitoring of the site. The project aims at creating an EGS by directly and systematically injecting cool water at relatively low pressure into a known High Temperature (about 280 to 350 C) Zone (HTZ) located under the conventional (240 C) steam reservoir at depths of {approx}3 km. Accurate micro-earthquake monitoring initiated before the start of the injection will be used as a tool for tracking the development of the EGS and monitoring changes in microseismicity. We first analyzed historic injection and micro-earthquake data from an injection well (Aidlin 11) located about 3 miles to the west of the new EGS demonstration area. Thereafter, we used the same modeling approach to predict the likely extent of the zone of enhanced permeability for a proposed initial injection in two wells (Prati State 31 and Prati 32) at the new EGS demonstration area. Our modeling indicates that the …
Date: October 20, 2010
Creator: Rutqvist, J.; Dobson, P. F.; Oldenburg, C. M.; Garcia, J. & Walters, M.
Object Type: Article
System: The UNT Digital Library
Gamma Spectrum from Neutron Capture on Tungsten Isotopes (open access)

Gamma Spectrum from Neutron Capture on Tungsten Isotopes

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Date: May 20, 2010
Creator: Hurst, A. M.; Summers, N. C.; Sleaford, B.; Firestone, R.; Belgya, T. & Revay, Z. S.
Object Type: Article
System: The UNT Digital Library
Heterogeneous nucleation of ice on anthropogenic organic particles collected in Mexico City (open access)

Heterogeneous nucleation of ice on anthropogenic organic particles collected in Mexico City

This study reports on heterogeneous ice nucleation activity of predominantly organic (or coated with organic material) anthropogenic particles sampled within and around the polluted environment of Mexico City. The onset of heterogeneous ice nucleation was observed as a function of particle temperature (Tp), relative humidity (RH), nucleation mode, and particle chemical composition which is influenced by photochemical atmospheric aging. Particle analyses included computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). In contrast to most laboratory studies employing proxies of organic aerosol, we show that anthropogenic organic particles collected in Mexico City can potentially induce ice nucleation at experimental conditions relevant to cirrus formation. The results suggest a new precedent for the potential impact of organic particles on ice cloud formation and climate.
Date: June 20, 2010
Creator: Knopf, D. A.; Wang, B.; Laskin, A.; Moffet, R. C. & Gilles, M. K.
Object Type: Article
System: The UNT Digital Library
Dynamic Simulation Studies of the Frequency Response of the Three U.S. Interconnections with Increased Wind Generation (open access)

Dynamic Simulation Studies of the Frequency Response of the Three U.S. Interconnections with Increased Wind Generation

Utility Systems Efficiencies, Inc. was tasked by Lawrence Berkeley National Laboratory (LBNL) to conduct dynamic simulation studies of the three U.S. interconnections (Eastern, Western, and Texas). The simulations were prepared in support of LBNL's project for the Federal Energy Regulatory Commission to study frequency-response-related issues that must be addressed to operate the power system reliably with large amounts of variable renewable generation. The objective of the simulation studies of each interconnection was to assess the effects of different amounts of wind generation on frequency behavior of each interconnection following a sudden loss of generation. The scenarios created to study these effects considered an operating circumstance in which system load is at or close to its minimum. The event studied was the sudden loss of the largest amount of generation recorded within each interconnection. The simulations calculated the impact of this event on interconnection frequency for three levels of wind generation. In addition to varying the amount of wind generation, the simulations varied the amount of operating reserves between a high level representative of current operating practices and a low level representative of the minimum required by present operating rules.
Date: December 20, 2010
Creator: Mackin, Peter; Daschmans, R.; Williams, B.; Haney, B.; Hung, R. & Ellis, J.
Object Type: Report
System: The UNT Digital Library
A NORMETEX MODEL 15 M3/HR WATER VAPOR PUMPING TEST (open access)

A NORMETEX MODEL 15 M3/HR WATER VAPOR PUMPING TEST

Tests were performed using a Model 15 m{sup 3}/hr Normetex vacuum pump to determine if pump performance degraded after pumping a humid gas stream. An air feed stream containing 30% water vapor was introduced into the pump for 365 hours with the outlet pressure of the pump near the condensation conditions of the water. Performance of the pump was tested before and after the water vapor pumping test and indicated no loss in performance of the pump. The pump also appeared to tolerate small amounts of condensed water of short duration without increased noise, vibration, or other adverse indications. The Normetex pump was backed by a dual-head diaphragm pump which was affected by the condensation of water and produced some drift in operating conditions during the test.
Date: December 20, 2010
Creator: Klein, J.; Fowley, M. & Steeper, T.
Object Type: Article
System: The UNT Digital Library
Daemen Alternative Energy/Geothermal Technologies Demonstration Program Erie County (open access)

Daemen Alternative Energy/Geothermal Technologies Demonstration Program Erie County

The purpose of the Daemen Alternative Energy/Geothermal Technologies Demonstration Project is to demonstrate the use of geothermal technology as model for energy and environmental efficiency in heating and cooling older, highly inefficient buildings. The former Marian Library building at Daemen College is a 19,000 square foot building located in the center of campus. Through this project, the building was equipped with geothermal technology and results were disseminated. Gold LEED certification for the building was awarded. 1) How the research adds to the understanding of the area investigated. This project is primarily a demonstration project. Information about the installation is available to other companies, organizations, and higher education institutions that may be interested in using geothermal energy for heating and cooling older buildings. 2) The technical effectiveness and economic feasibility of the methods or techniques investigated or demonstrated. According to the modeling and estimates through Stantec, the energy-efficiency cost savings is estimated at 20%, or $24,000 per year. Over 20 years this represents $480,000 in unrestricted revenue available for College operations. See attached technical assistance report. 3) How the project is otherwise of benefit to the public. The Daemen College Geothermal Technologies Ground Source Heat Pumps project sets a standard for …
Date: May 20, 2010
Creator: Robert C. Beiswanger, Jr.
Object Type: Article
System: The UNT Digital Library
Automatic Fault Characterization via Abnormality-Enhanced Classification (open access)

Automatic Fault Characterization via Abnormality-Enhanced Classification

Enterprise and high-performance computing systems are growing extremely large and complex, employing hundreds to hundreds of thousands of processors and software/hardware stacks built by many people across many organizations. As the growing scale of these machines increases the frequency of faults, system complexity makes these faults difficult to detect and to diagnose. Current system management techniques, which focus primarily on efficient data access and query mechanisms, require system administrators to examine the behavior of various system services manually. Growing system complexity is making this manual process unmanageable: administrators require more effective management tools that can detect faults and help to identify their root causes. System administrators need timely notification when a fault is manifested that includes the type of fault, the time period in which it occurred and the processor on which it originated. Statistical modeling approaches can accurately characterize system behavior. However, the complex effects of system faults make these tools difficult to apply effectively. This paper investigates the application of classification and clustering algorithms to fault detection and characterization. We show experimentally that naively applying these methods achieves poor accuracy. Further, we design novel techniques that combine classification algorithms with information on the abnormality of application behavior to …
Date: December 20, 2010
Creator: Bronevetsky, G; Laguna, I & de Supinski, B R
Object Type: Article
System: The UNT Digital Library
Power and Frequency Control as it Relates to Wind-Powered Generation (open access)

Power and Frequency Control as it Relates to Wind-Powered Generation

This report is a part of an investigation of the ability of the U.S. power system to accommodate large scale additions of wind generation. The objectives of this report are to describe principles by which large multi-area power systems are controlled and to anticipate how the introduction of large amounts of wind power production might require control protocols to be changed. The operation of a power system is described in terms of primary and secondary control actions. Primary control is fast, autonomous, and provides the first-line corrective action in disturbances; secondary control takes place on a follow-up time scale and manages the deployment of resources to ensure reliable and economic operation. This report anticipates that the present fundamental primary and secondary control protocols will be satisfactory as wind power provides an increasing fraction of the total production, provided that appropriate attention is paid to the timing of primary control response, to short term wind forecasting, and to management of reserves for control action.
Date: December 20, 2010
Creator: Lacommare, Kristina S H
Object Type: Report
System: The UNT Digital Library
CLOSE-OUT REPORT FOR HYS ELECTROLYZER COMPONENT DEVELOPMENT WORK AT SAVANNAH RIVER NATIONAL LABORATORY (open access)

CLOSE-OUT REPORT FOR HYS ELECTROLYZER COMPONENT DEVELOPMENT WORK AT SAVANNAH RIVER NATIONAL LABORATORY

The chemical stability, sulfur dioxide transport, ionic conductivity, and electrolyzer performance have been measured for several commercially available and experimental proton exchange membranes (PEMs) for use in a sulfur dioxide depolarized electrolyzer (SDE). The SDE's function is to produce hydrogen by using the Hybrid Sulfur (HyS) Process, a sulfur based electrochemical/thermochemical hybrid cycle. Membrane stability was evaluated using a screening process where each candidate PEM was heated at 80 C in 63.5 wt. % H{sub 2}SO{sub 4} for 24 hours. Following acid exposure, chemical stability for each membrane was evaluated by FTIR using the ATR sampling technique. Membrane SO{sub 2} transport was evaluated using a two-chamber permeation cell. SO{sub 2} was introduced into one chamber whereupon SO{sub 2} transported across the membrane into the other chamber and oxidized to H{sub 2}SO{sub 4} at an anode positioned immediately adjacent to the membrane. The resulting current was used to determine the SO{sub 2} flux and SO{sub 2} transport. Additionally, membrane electrode assemblies (MEAs) were prepared from candidate membranes to evaluate ionic conductivity and selectivity (ionic conductivity vs. SO{sub 2} transport) which can serve as a tool for selecting membranes. MEAs were also performance tested in a HyS electrolyzer measuring current density versus …
Date: January 20, 2010
Creator: Colon-Mercado, H.; Elvington, M. & Hobbs, D.
Object Type: Report
System: The UNT Digital Library
ACS Symposium Support (open access)

ACS Symposium Support

The funds from this DOE grant were used to help cover the travel costs of five students and postdoctoral fellows who attended a symposium on 'Hydration: From Clusters to Aqueous Solutions' held at the Fall 2007 American Chemical Society Meeting in Boston, MA, August 19-23. The Symposium was sponsored by the Physical Chemistry Division, ACS. The technical program for the meeting is available at http://phys-acs.org/fall2007.html.
Date: February 20, 2010
Creator: Jordan, Kenneth D.
Object Type: Report
System: The UNT Digital Library
Engineering Thermotolerant Biocatalysts for Biomass Conversion to Products (open access)

Engineering Thermotolerant Biocatalysts for Biomass Conversion to Products

Lignocellulosic biomass is a promising feedstock for producing renewable chemicals and transportation fuels as petroleum substitutes. Fermentation of the cellulose in biomass in an SSF process requires that the properties of the microbial biocatalyst match the fungal cellulase activity optima for cost-effective production of products. Fermentation of the pentose sugars derived from hemicellulose in biomass is an additional asset of an ideal biocatalyst. The microbial biocatalyst used by the industry, yeast, lacks the ability to ferment pentose sugars. The optimum temperature for growth and fermentation of yeast is about 35°C. The optimum temperature for commercially available cellulase enzymes for depolymerization of cellulose in biomass to glucose for fermentation is 50-55 °C. Because of the mismatch in the temperature optima for the enzyme and yeast, SSF of cellulose to ethanol (cellulosic ethanol) with yeast is conducted at a temperature that is close to the optimum for yeast. We have shown that by increasing the temperature of SSF to 50-55 °C using thermotolerant B. coagulans, the amount of cellulase required for SSF of cellulose to products can be reduced by 3-4 –fold compared to yeast-based SSF at 35°C with a significant cost savings due to lower enzyme loading. Thermotolerant Bacillus coagulans strains …
Date: May 20, 2010
Creator: K. T. Shanmugam, L. O. Ingram and J. A. Maupin-Furlow
Object Type: Report
System: The UNT Digital Library